July 15, 2020
It’s been a while since our last check-in. One of the things I was surprised by when I started in orchard work was the relative slowdown in urgency after July 1. Having grown up on a dairy farm, where there’s no break, and summer means haying season on top of all the other chores, a chance to take a breather in summer is welcome.
But that doesn’t mean there’s nothing to do in the orchard, and activities done (or not done) now can greatly affect your crop. Here are some of the things to keep in mind right now:
Insects: Apple maggot fly (AMF) is active in most Vermont orchards. Red sticky traps should have been hung at the beginning of the month, and five flies per baited trap, or one if not using baited lures, should indicate a need to treat. Assail is the most common material that growers are using these days, although many others are also effective. As always, see the New England Tree Fruit Management Guide for specific details. Organic growers may have success using Surround at this time, although the residue will need to be removed from fruit at harvest. Entrust has some efficacy against AMF, but should be used with a feeding stimulant like sugar to increase feeding by flies. Codling moth (CM)second generation egg hatch is still a bit away, we usually aim for treatment around 1260 degree days (base 50F) after the first trap capture biofix (we’re at 907 in South Burlington as of today). Obliquebanded leafrollers should be active soon as well, and I’d imagine that materials applied to target CM (unless using very specific materials like codling moth granulosis virus) will take care of hatching larvae.
Mites aren’t really insects, but I’ll include them here. The hot, dry weather has been very conducive to mite population flare-up, both for European red mite and for two-spotted spider mite. These pests are worth scouting for, and an average of over 5 mites per leaf (choose mid-aged leaves on terminals) may warrant treatment. The best ways to avoid mite problems are measure to protect beneficial mites and insects that eat them. That means avoidance of pyrethroid, carbamate, and organophosphate insecticides in general, as well as a thorough oil treatment in spring. Still, if you are in mite trouble, there are many materials available to help manage them.
Diseases: Apple scab should be done, it was a pretty easy year on that front. Sooty blotch and flyspeck are now the main cosmetic diseases, along with bitter rot and black rot that can destroy fruit. Although it’s dry, maintaining a minimum residue of a fungicide like Captan, Topsin, or a strobilurin will help to keep diseases at bay until harvest. We’re on a three-week schedule at the UVM orchards, but it’s really dry there and we do not wholesale fruit so a little cosmetic damage from SBFS is acceptable. Finally, keep looking for and cutting out fire blight.
Horticulture: Now is the time to start summer pruning to get some sunlight into vigorous trees and improve airflow and spray penetration. In most cases, summer pruning may not be necessary except to correct for occasional broken limbs or branches growing out into the drive row. But in many Vermont orchards where semi dwarf trees are still common, a light haircut can improve light penetration, red fruit color, and overall pest management and fruit quality. I tell my pruners that I want to see the whole trunk- that means removing vegetative shoots tat are blocking light from penetrating into the tree canopy. Fruit don’t need to be 100% exposed, dappled light is okay, but they can’t be in the shade.
It’s important to be maintaining calcium sprays, especially on large-fruited cultivars and doubly especially on Honeycrisp. Four to eight applications are recommended, especially on Honeycrisp, to reduce bitter pit. That may mean making extra trips through the orchard just to spray calcium. Most times, it can be mixed into the tank with other pesticides, as long as any pH requirements are met for the materials you’re using.
Keep running water if you can. It’s really dry out there, not that you need me to tell you that.
COVID-19: As harvest nears, I’ll get more materials out regarding impact of the pandemic on farm operations. For now, I’ll point you to Verm Grubinger’s excellent resource list for vegetable and berry growers. You will need a plan this year, whether harvesting for wholesale, selling retail, or opening for PYO.